A study investigated the reliability of international students' English-as-a-Second-Language (ESL) class performance as a predictor of academic performance. Subjects were 169 international students at Portland State University (Oregon) whose freshman and sophomore grade point averages (GPAs) and English language test scores for each language skill (listening, speaking, reading, writing) were analyzed and correlated with demographic characteristics (gender, major type, age, nationality, number of ESL classes taken, previous English-language college experience, educational level, university entry date). Results were mixed. While ESL and academic grades correlated strongly for some groups, it was unclear which variables had the strongest effect because of subgroup composition. Two clear patterns emerged: (1) ESL students with 12 or more ESL classes maintained consistent academic GPAs across time, while others (ESL and non-ESL) had initially higher but declining GPAs; and (2) groups with strong ESL-academic GPA correlations tended to do better in college. Language scores were correlated to both ESL and academic grades. (Author/MSE)